<!DOCTYPE html>
<script>
window.onload = function()
{
    if (!window.testRunner || !window.internals)
        return;

    testRunner.dumpAsText();
    document.body.offsetTop;
    internals.startTrackingRepaints(document);

    document.getElementById('a').style.top = '400px';
    document.getElementById('b').style.left = '400px';

    document.body.offsetTop;
    var layerTree = internals.layerTreeAsText(document, internals.LAYER_TREE_INCLUDES_INVALIDATIONS);
    internals.stopTrackingRepaints(document);
    document.getElementById('result').textContent = layerTree.indexOf('repaint') == -1 ? 'SUCCESS' : 'FAIL';
};
</script>

<style>
.fixed {
    position: fixed;
    top: 200px;
    left: 200px;
    width: 100px;
    backface-visibility: hidden;
}
</style>

There should be no repaint when the divs are moved.
<div class="fixed" id="a">A</div>
<div class="fixed" id="b">B</div>
<pre id="result"></pre>
